Ovarian function in amenorrheic and menstruating users of a levonorgestrel-releasing intrauterine device

The ovarian function of 20 healthy users of a levonorgestrel-releasing intrauterine device was studied by measurements of plasma estradiol, progesterone, and levonorgestrel concentrations. Eight subjects were amenorrheic, and 12 had regular menstrual bleeding. Seventy-five percent of the subjects in both groups had ovulatory cycles. There was no difference between the mean levonorgestrel concentrations in the amenorrheic and regularly menstruating subjects. Estradiol function was undisturbed in the amenorrheic subjects with ovulatory cycles. The effect of levonorgestrel as a cause of amenorrhea is thought to be mainly of local nature. The intrauterine administration of levonorgestrel had only an occasional and weak effect on ovarian function.

Plasma levels of levonorgestrel, gestodene, norethisterone and cyproterone acetate on single-dose subcutaneous administration in oily solution in the rat, beagle and rhesus monkey

This report describes the pharmacokinetics of levonorgestrel, gestodene, norethisterone and cyproterone acetate following subcutaneous administration of oily solutions in the rat, beagle dog and rhesus monkey. The plasma levels of the progestogens were measured by means of specific radioimmunoassays. Half-lives calculated for the disposition process of a particular metabolically unchanged drug in plasma revealed marked differences in different animal species. Furthermore, comparison of the different progestogens showed large variations in this parameter in all the animal species. It became obvious that there are physico-chemical properties as well as metabolic rate limitations effecting the release and elimination of synthetic progestogens administered in oily solution. The results are compared with the half-lives of these progestogens administered intravenously as reported previously. A prolongation of half-life as a result of the depot effect of subcutaneous administration was demonstrated for all the progestogens in the rat, the beagle dog and the rhesus monkey.

Pituitary and ovarian function and clinical performance during the use of a levonorgestrel-releasing intracervical contraceptive device

A levonorgestrel-releasing intracervical device (ICD) was inserted postmenstrually to twenty-one voluntary women. Eight subjects gave blood samples twice a week during the initial three months of use of the ICD and during the seventh and twelfth months of use. Clinical performance was studied; plasma concentrations of levonorgestrel were measured by radioimmunoassay and the effects of the treatment on pituitary and ovarian function were determined by assaying plasma concentrations of LH, FSH, estradiol and progesterone. The results of the first year are presented. Dysmenorrhea, menstrual flow and the number of days of bleeding decreased during the first treatment year. Three spontaneous expulsions occurred; two at the very beginning of the treatment and one after six months of use. Side-effects were few. The plasma level of levonorgestrel remained fairly constant during the observation time of 12 months. Thirty-one of the 36 cycles were ovulatory as judged by plasma progesterone elevations. No pregnancies occurred during the study period of one year.

The effect of cotrimoxazole on oral contraceptive steroids in women

Nine women taking long-term oral contraceptive steroids (Trinordiol) were studied during a cycle while taking cotrimoxazole (1 gm twice daily) and the results were compared to the previous control cycle. During the cotrimoxazole cycle, there was a significant increase in the plasma concentration of ethynylestradiol (EE). In plasma samples taken on 4 successive days 10-12 hours after dosing, the plasma EE concentration rose from 29.3 +/- 5.0 pg/ml to 38.2 +/- 5.8 pg/ml (mean +/- S.E. P less than or equal to 0.02). In samples taken 24 hours after dosing, the increase was from 18.9 +/- 2.5 pg/ml to 27.8 +/- 4.0 pg/ml (P less than or equal to 0.05). Plasma F.S.H. values in these latter samples, decreased from 4.8 +/- 0.6 mIu/ml to 3.4 +/- 0.5 mIu/ml (P less than or equal to 0.01). No significant changes were noted in the plasma concentrations of levonorgestrel or progesterone. The rise in plasma concentration of EE during cotrimoxazole therapy is attributed to an inhibition of the metabolism of EE by cotrimoxazole as has been shown with other drugs. Short courses of cotrimoxazole are unlikely to cause any adverse effects on contraceptive control when given to women taking long-term oral contraceptive steroids.

Levonorgestrel plasma levels during continuous administration with different models of subdermal implants

Plasma concentrations of levonorgestrel were determined in women using subdermal levonorgestrel implants. One group had 6 Silastic capsules (NORPLANT), one group had 4 and one group had 6 covered Silastic rods for variable lengths of time. Levonorgestrel concentrations remained constant around 0.4 ng/ml up until 6 years of use in the Norplant group. The observation period was shorter for the covered rods; plasma concentrations were, however, constant around 0.55 ng/ml and 0.70 ng/ml for 3.5 years with the 4 rods and 6 covered rods, respectively. The difference in mean levonorgestrel concentrations between the three groups were statistically significant (p less than 0.0005). Plasma levels of levonorgestrel were twice to three times higher in blood obtained from the arm with the implants compared to the levels found in the other arm. The application of a tourniquet for variable periods before blood sampling did not influence the plasma concentrations of levonorgestrel.

Tissue concentrations of levonorgestrel in women using a levonorgestrel-releasing IUD

Thirteen women who were scheduled for hysterectomy volunteered for the study. Nine women had a levonorgestrel-releasing intrauterine contraceptive device inserted between 36 and 49 days prior to surgery and four women were on oral levonorgestrel treatment for 7 days prior to surgery. After the surgical removal of the uterus, samples of endometrial, myometrial, fallopian tube and fat tissue were obtained. Methods for measuring tissue concentrations of levonorgestrel were developed and the uptake of levonorgestrel by fat tissue in vitro was studied. The concentrations of levonorgestrel in myometrial, fallopian tube and fat tissue were all of the same order, of between 1 and 5 ng/g of wet weight of tissue, in both the intrauterine device group and the orally treated group. In the endometrium the levonorgestrel concentrations were many-fold higher in the intrauterine device group. The in vitro experiments showed a rapid uptake of levonorgestrel and an unsaturability of the fat tissue by the steroid at the concentrations used. The fat tissue concentrations of levonorgestrel correlated with the plasma concentrations.

Plasma progesterone levels during long-term treatment with levonorgestrel silastic implants

Plasma progesterone levels were measured in 113 women using a subdermal implant containing 200 mg levonorgestrel (NORPLANT) in an attempt to assess the roles of anovulation and inadequate luteal function in the contraceptive action of this method. Twenty-two women using an IUD (Copper T 200) served as a control group. Blood samples were taken twice a week for 6 consecutive weeks. This was done one to four times in each subject during the first 7 years after insertion of NORPLANT. Plasma progesterone was measured by a specific RIA and criteria based upon normal values in this laboratory were used to define each set of samples as ovulatory, uncertain or anovulatory. The rate of anovulation varied between 25 and 80% throughout the 7 years. The highest rate was observed during the first year of treatment of treatment. The rate of anovulation was significantly correlated with the plasma levels of levonorgestrel. Varying degrees of inadequate corpus luteum function were detected among NORPLANT users. All sets of samples in the control group were ovulatory and compatible with normal luteal function. These results clearly show that continuous administration of levonorgestrel by means of NORPLANT interferes with ovulation and/or luteal function in a significant proportion of cycles throughout the first 7 years of use.

Puerperal insertion of a copper-releasing and a levonorgestrel-releasing intrauterine contraceptive device

A copper-releasing IUD and levonorgestrel-releasing IUDs releasing 30 micrograms and 10 micrograms levonorgestrel per day were inserted six weeks after delivery in 110 volunteers. During the treatment, events and patterns of bleeding were recorded and plasma levonorgestrel concentrations were measured. The number of events in one year of follow-up was very low, four removals out of 40 in the copper-releasing IUD group and five removals out of 70 in the levonorgestrel-releasing IUD group. Bleeding and spotting was significantly more common after insertion of a levonorgestrel-releasing IUD than a copper-releasing IUD, but it was scanty and well-tolerated. After three months, levonorgestrel-releasing IUD patients had less bleeding and spotting than the copper-releasing IUD patients. No pregnancies occurred during the study period. There were two uterine perforations with a uterine sound at the insertion. In the 30-micrograms per day levonorgestrel-releasing IUD group, initially high plasma levonorgestrel concentrations reached a plateau four weeks after the insertion. In the 10-micrograms per day levonorgestrel-releasing IUD group, the plasma concentrations of levonorgestrel stabilized after the initial two weeks.

Serum lipoprotein and apolipoprotein changes during treatment with a contraceptive vaginal ring containing levonorgestrel and estradiol

Contraceptive vaginal rings containing estradiol and levonorgestrel were used by 22 women during 219 cycles. The estrogenicity was low and the daily dose of levonorgestrel was about 290 micrograms. The triglyceride and cholesterol concentrations decreased in whole serum and, to varying degrees, in the different lipoprotein classes. The most consistent change was a 25% (p less than 0.001) reduction in the cholesterol content of the high-density lipoprotein (HDL) fraction. The cholesterol concentration in low-density lipoprotein decreased by 11% after the first 3 months, but increased during the ensuing 9 months of treatment to regain pretreatment level. Percentage-wise, the apolipoprotein B and A-I concentrations, determined by rocket immunoelectrophoresis, were less affected than the LDL- and HDL-cholesterol concentrations. The composition of the LDL and HDL particles seemed thus to alter during the treatment. The pronounced effect on the HDL levels seen is consistent with earlier findings of a dose-dependent, androgenic effect of gestagens derived from 19-nortestosterone. However, the low basal level of LDL and its further decrement during treatment alleviate the supposedly unfavorable effect of HDL reduction from the atherogenic point of view.

A competitive protein binding radioassay for 17alpha-ethynylestradiol in human plasma

A competitive protein binding radioassay system using a rabbit uterine cytosol preparation for the measurement of ethynylestradiol [EE2e] in human plasma has been developed. Sephadex LH-20 column chromatography is used for the separation of the estrogens prior to assay. EE2 levels were measured in 23 normotensive subjects on contraceptive pills containing either 50 mug of EE2 or mestranol. The EE2 values ranged from 144 to 248 pg with a mean of 211 pg (S.D. +/- 37.94). The method is sensitive enough to detect 25 pg of EE2 in plasma. The intra- and inter-assay coefficients of variation were 7.54% and 10.75%, respectively. Water blanks and plasma blanks from subjects not on pills gave negligible readings for EE2.